what turbo are you running. If your getting true compressor surge on the turbo, than you need to lower your boost settings or change the settings so the boost builds slower. Compressor surge means the turbo is building more boost than it can support at that engine rpm ( usually poorly matched turbo and engine combination ).

If it is not due to compressor surge you could be having fuel or ignition issues.

It would help with a bit more info about your setup (how close to stock are you), and the circumstances where you see the surging. If your getting any CEL you need to get that code pulled and come back to the forum with that info.